Swap OM612 and OM647 engine

[220629]

Swapping install replace transfer 2002 2003 2004 2005 2006 2.7L 5 cylinder

I found searching for this info a bit more difficult than it should have been. A compilation of engine swap information.

Basically the short blocks can be swapped OM612 and OM647, but there are specific issues depending upon what direction the swap entails.

As the T1N models age out replacing an engine may be something under consideration. The NAS aka NAFTA 2001 - 2003 with OM612 5 cylinder engine is different from the NAS aka NAFTA OM647 5 cylinder engine as to fueling and some other differences.

A basic stripped engine swap is possible between those models, but not a direct complete engine drop in.

Some info. Thanks goes to azzm3.

Yes the injector connectors are the same and are triggered by OM647 ECU with no issues.
Complete fuel rail from OM647 is also transferred over. You change the front plate where the low pressure pump mounts with one from OM647. Also OM647 high pressure pump is used and it does mount up like its suppose to. In simple terms you strip OM612 to block and head leaving injectors in and dress it up with OM647 components wiring,turbo,rail,pump etc. Everything functions like it should with no warning lights and limp modes (I use DRB3 for all diag on T1n). I have driven swaps like these cross country with no issues.

This is a reply to Aqua Puttana

Added:
Do your research before going too far.

Some input from Doktor A.

It appears you are asking whether a 647 long block (cylinder head included) can be used.

The complication you have is mounting and driving the mechanical feed pump and the 612 high pump.

The 647 intake cam lacks the drive extension for the 612 feed pump and the 647 upper chain ramp plate lacks the opening and threaded mounting holes for the feed pump.

The 647 cylinder heads' bolt pattern for the high pump will not allow mounting of your 612 high pump.

Doktor A

And comments by Dennis Lindenengineering that the lower end is ok.

Rule of thumb
Everything above the block is different including the FI equipment .
Dennis

No
Simply because the HP injection pump aperture in the head is different the older head and some minor chain guide differences. AND the exhaust valves are sized differently
Dennis

A follow up: As your luck would have it, I needed to find my stash of 612 pistons for an engine repair.

My hunch was correct, the 612 piston crowns' valve reliefs are sized for the larger diameter tulip heads of the 612 valves and the 647 valve reliefs are accordingly smaller.

Thus it appears risky to bolt a 612 head onto a 647 short block.

Doktor A

As always, clicking on the blue arrow icon within any quote box will take you to the original post/thread.

Another thread discussion of engine swap.

https://sprinter-source.com/forum/showthread.php?t=50846
https://sprinter-source.com/forum/showthread.php?p=555980

vic

 

[cesaredoesit]

I swapped a 612 head onto a 647 block with no issue. You have to change the plate on the front of the head and use all of the FI equipment from the 647. 40k miles now and still running great. I've run 70-75 mph with a trailer and an s10 on it from Texas to Ohio.

 

[ChrisCO]

Ok despite my efforts of searching, reading, trying to deduce what this and ither threads are trying to ask, I figured i'd attempt to revive this thread with a hopefully clearer question and problem statement.

My '03 has a bad engine. Rebuild costs are too high and the OM612 seems to be too hard to find a good used one for a reasonable price.

I've found a local gentleman with a fleet of sprinters, and subsequently he has a good, low mile motor out of an 05 for a good price.

I'm interested in whether the long block from the 05 can be used in the following configuration:

Use '05 block & head, use '03 turbo, my original '03 wiring harness & ECU, '03 injectors, '05 late pump and fuel rail, '05 intake manifold.

Will all sensors plug and operate correctly?
Will '05 egr plug plug into 03 harness?
Will the 03 injectors work with the late pump?

Thanks

 

[schwarzwaldsprinter]

basically the same engines. However engine harness and a few other items must be used from the 612 engine. If you know what you are doing it is easy, IMO.
Good luck.
Sven

 

[ChrisCO]

basically the same engines. However engine harness and a few other items must be used from the 612 engine. If you know what you are doing it is easy, IMO.
Good luck.
Sven

Do you have a breakdown of what those "few other items" are?

I'm confident in my abilities but this IS my first sprinter 'rodeo' so I'm attempting to gather specific details and validate information I've happened upon in order to build a plan, a parts list, and know I'm making an informed decision.

 

[schwarzwaldsprinter]

You will learn a lot here:

 

[schwarzwaldsprinter]

The OM612 and OM647 are both 2.7-liter, inline-5 turbocharged diesel engines used by Mercedes-Benz, but the OM647 is a later evolution of the OM612. A key difference is the fuel system; the OM647 lacks the low-pressure fuel pump found on the OM612 and has a different high-pressure pump. The OM647 also features a different intake manifold. Despite these differences, the engines share a similar long block design, and components can be swapped between them with some sensor adjustments.

Here's a more detailed breakdown:

• Fuel System:
  The OM647 has a simpler fuel system compared to the OM612, lacking the low-pressure fuel pump and featuring a different high-pressure pump.
  
  
• Intake Manifold:
  The OM647 has a redesigned intake manifold.
  
  
• Similarities:
  Both are 2.7-liter inline-5 turbocharged diesel engines used in various Mercedes-Benz vehicles, including the Sprinter van.
  
  
• Interchangeability:
  While there are differences, the long blocks of both engines are similar enough that they can be swapped with some adjustments for sensors.

You can find much more online and here in the forum.

Sven

 

[schwarzwaldsprinter]

 

[Midwestdrifter]

There are some non-tapped holes on the 612 head that need drilled and tapped. The timing cover is different between them (obviously as one has an extra fuel pump). I believe it must be changed. If so this is non trivial. I don't recall off hand if the timing cover comes off easily with the head installed.

There are some minor bracketry items that need transferred.


Making most of the 647 injection components work on the 612 isn't proven as far as I know (some folks have gotten limited success). The fuel rail should work on the 612 ECM, but using the 612 fuel pump is highly recommended for compatibility reasons.

The EGRs are interchangeable wiring wise (might need to swap connectors). So using the 647 manifold works fine.

I suggest using the 612 injectors. Those are what the ECM is expecting. The fuel pump has no impact on the injectors, as the pressure is controlled in real time by the ECM.

The crank and cam sensors are identical between them. All the accessories are the same.

 

[ChrisCO]

The OM612 and OM647 are both 2.7-liter, inline-5 turbocharged diesel engines used by Mercedes-Benz, but the OM647 is a later evolution of the OM612. A key difference is the fuel system; the OM647 lacks the low-pressure fuel pump found on the OM612 and has a different high-pressure pump. The OM647 also features a different intake manifold. Despite these differences, the engines share a similar long block design, and components can be swapped between them with some sensor adjustments.

Here's a more detailed breakdown:

• Fuel System:
  The OM647 has a simpler fuel system compared to the OM612, lacking the low-pressure fuel pump and featuring a different high-pressure pump.
  
  
• Intake Manifold:
  The OM647 has a redesigned intake manifold.
  
  
• Similarities:
  Both are 2.7-liter inline-5 turbocharged diesel engines used in various Mercedes-Benz vehicles, including the Sprinter van.
  
  
• Interchangeability:
  While there are differences, the long blocks of both engines are similar enough that they can be swapped with some adjustments for sensors.

You can find much more online and here in the forum.

Sven

Thank you!!

 

[ChrisCO]

There are some non-tapped holes on the 612 head that need drilled and tapped. The timing cover is different between them (obviously as one has an extra fuel pump). I believe it must be changed. If so this is non trivial. I don't recall off hand if the timing cover comes off easily with the head installed.

There are some minor bracketry items that need transferred.


Making most of the 647 injection components work on the 612 isn't proven as far as I know (some folks have gotten limited success). The fuel rail should work on the 612 ECM, but using the 612 fuel pump is highly recommended for compatibility reasons.

The EGRs are interchangeable wiring wise (might need to swap connectors). So using the 647 manifold works fine.

I suggest using the 612 injectors. Those are what the ECM is expecting. The fuel pump has no impact on the injectors, as the pressure is controlled in real time by the ECM.

The crank and cam sensors are identical between them. All the accessories are the same.

Seems doable in the driveway?

 

[Midwestdrifter]

Seems doable in the driveway?

I have completely rebuilt an engine in my driveway, so yes, its doable. There isn't any machining to be done, if that is what you are asking. Be prepared to need to wait a couple days for random parts (O rings etc) as there is a lot of old parts which like to fail when taken apart.

The caveat is that I haven't tried swapping an OM612 timing cover onto the 647, so I can't 100% confirm what is required. You will need to do this in order to drive the 612 low pressure pump. There is an adapter which needs attached to the intake came to drive the pump as well.

Plenty of good photos of the OM647 top end in this thread.

Possible Cracked Piston: Investigation and Rebuild

I'm wanting to know if that test is useful at all for finding a massively overfueling injector. @jrod5150 doesn't think it's that useful. It can definitely help to determine which of the five injectors is massively overfueling. It is not useful for monitoring nominal wear and age by comparing...

sprinter-source.com

 

[tumble weed family]

Call.me I did this and I drive it all the time worked out all the kinks already. Mostly u will need parts from 2 harneses and some wire and heatshrink fuel pump relay wires fuel line a fuel y for the pressure sensor and a bunch of other bits. But it works no problem as long as younlike wiring